Synthesizing ideas from event semantics and psycholinguistics, this monograph provides a new perspective on the processing of linguistic aspect and aspectual coercion. Confronting alternative semantic accounts with experimental evidence, the author develops a comprehensive model of online aspectual interpretation. The first part of the book critically reviews competing theoretical accounts of aspectual coercion. As an analytical tool the author introduces a computational model based on the event calculus by Hamm & van Lambalgen (2005) which makes use of planning formalisms from artificial intelligence. Detailed predictions from this framework are then tested in the experimental work reported in the second part. The focus here is on such questions as: Is aspectual coercion a uniform phenomenon or must we distinguish different types? Is aspect processed incrementally or is it computed only at the clause boundary? And finally, what insights can event related potentials yield about how the brain resolves local aspectual mismatch?